JPH02293153A - Ink jet head - Google Patents

Abstract

PURPOSE:To stabilize the delivery of an ink, to eliminate troubles in discharging the ink, and to prevent the ink from accidentally discharging from nozzles by providing a vertical groove connecting ink retaining grooves to an ink storing part and also connecting an air port to the ink storing part. CONSTITUTION:In a substrate 1, an ink flow path is provided upward of an means for discharging an ink drip from a nozzle 8. An ink tank 11 is mounted on the upper surface of the substrate 1. An ink retaining body 12 is incorporated in the lower half part of the ink tank 11. A space above the ink retaining body 12 serves as an ink storing part 21. A through hole 13 connecting the ink storing part 21 to the ink flow path of the substrate 1 is provided in the ink rataining body 12. An ink inducing rod 19 is inserted into the through hole 13, and ink retaining grooves 15 are provided for holding an ink that is extruded from the ink storing part 21 by the inner pressure increase in the ink tank 11. Furthermore, a vertical groove 16 connecting the ink retaining grooves 15 to the ink storing part 21 and also connecting an air port 18 to the ink storing part 21 is provided.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an inkjet head capable of recording by ejecting and flying ink droplets from a nozzle and depositing the ink on recording paper. The present invention relates to an integrated disposable inkjet head.

(Prior Art) Conventionally, a disposable inkjet head described in Japanese Patent Application Laid-Open No. 59-207263 is known, and the conventional example is a shrinkable inkjet head made of flexible silicone rubber or the like. A possible ink reservoir is a component/element. The ink reservoir contracts as the ink is consumed, but on the other hand, it tries to restore its original shape, and the surface tension of the ink tries to pull the meniscus formed in the nozzle portion into the reservoir. Therefore, the ejection of ink from the nozzle becomes unstable, the ejected ink droplets become smaller, and the flying speed and direction of the ink droplets become inappropriate, making normal printing impossible. There were negative effects. As ink consumption continues, the restoring force of the ink reservoir becomes stronger, and the ink suction force at the nozzle increases, making it impossible for the ink to form a meniscus at one nozzle due to surface tension. This may cause air to enter the head from the nozzle portion, making it impossible to eject ink even though a considerable amount of ink remains in the ink reservoir.

In addition, a common problem with inkjet heads is that immediately after ink is ejected from the nozzle, the ink is not quickly supplied to the gap inside the nozzle, so air enters the head from the nozzle and accumulates as air bubbles near the nozzle. This poses a problem in that ink ejection is hindered.

(Problems to be Solved by the Invention) The present invention provides stable ink ejection from the nozzle portion, and even if air enters the head from the nozzle portion and bubbles are generated, the air bubbles will cause the ink to be ejected. In addition, if the air that has entered the ink tank to replace the ink expands due to temperature rise, and the internal pressure increases, the ink will be pushed out and unexpectedly ejected from the nozzle. To provide an inkjet head integrated with an ink tank that can be disposed of and prevents accidents.

(Means for Solving the Problems) In order to achieve the above object, the inkjet head of the present invention includes a nozzle and a means for ejecting ink droplets from the nozzle at the lower end of the support. An ink flow path is provided above the means for ejecting ink droplets from the nozzle, an ink tank is mounted on the upper surface of the support, and an ink reservoir is installed in the lower half of the ink tank. The space above the ink reservoir is used as an ink reservoir, and the ink reservoir is provided with a through hole that communicates the ink reservoir with the ink flow path of the support, and an ink guiding rod is inserted into the through hole. Additionally, an ink storage groove is provided for storing ink pushed out from the ink storage section by an increase in internal pressure in the ink tank, and further, a vertical groove is provided that communicates the ink storage groove with the ink storage section and also communicates the air port with the ink storage section. It is characterized by the provision of.

(English example) An embodiment of the present invention will be described based on the drawings.

First, the substrate (2) is attached to the side surface of the support (1),
The substrate (2) is further provided with a nozzle plate (3) with an appropriate gap (
4) (see Fig. 4) is provided and joined. Substrate (2
), a plurality of heating resistors (5) are arranged as shown in FIG. 3, and each heating resistor (5) is connected to a contact (7) by a wiring (6). Nozzles (8) are arranged on the nozzle plate (3) at positions facing each heating resistor (5). An ink channel (9) (see Fig. 4) is provided on the upper surface of the support (1) and communicates with the gap (4) provided between the substrate (2) and the nozzle plate (3). An ink tank fitting recess aI is formed. The ink tank αυ has an ink storage body o′;! The space above the ink reservoir α2 is made into an ink reservoir Qυ, and the lower end of the ink reservoir a7J is watertightly fitted into the ink tank fitting recess αl on the upper surface of the support. There is. Ink reservoir (I
A through hole α that opens from the upper end to the lower end is provided at a position slightly offset from the center of the z, and a large number of horizontal blades I are provided on the outer periphery in a vertically lined manner. . Ink storage grooves with a width sufficient to cause capillary action are provided in the circumferential direction between each blade α4, and vertical grooves in the vertical direction communicating with each ink storage groove α9 are provided in a part of the blade α4. αe is formed to open at the upper end, and cutouts (17a) (17b) are formed in a part of each blade αa at a position opposite to the vertical groove αe. In addition, the vertical groove (16l is the ink storage groove α9
Similarly, it is formed with a width that causes capillary action. The width of the ink storage groove α9 is still gradually increasing from the upper end to the lower end, and the upper ink storage groove α9
is formed so that the capillary action is stronger. An air port a& is provided in the side surface of the lower end of the ink tank αυ.
a) (17b) and the ink reservoir Cυ above the ink reservoir az via the vertical l1l line. The lower end of the through hole α3 of the ink reservoir α2 communicates with the ink channel {9} of the support (1), and an ink guiding rod αj is inserted through the through hole α. Of course, the ink reservoir Cυ above the ink reservoir α is filled with ink. The ink tank aυ is made of a transparent material so that the amount of ink can be visually checked from the outside. In this embodiment, the entire inkjet head is configured to be disposable, but the ink tank αυ may be made into a cartridge so that only the ink tank can be replaced.

The ink ■ is supplied from the ink reservoir Qυ to the ink channel (9} while passing through the ink guide rod α of the ink reservoir (I), and from there it is further passed through the ink flow path (9} between the nozzle plate (3) and the substrate (2). is supplied to the gap (4), and from the nozzle (8) at a position facing the heating resistor (5) due to a state change that occurs when a thermal pulse is applied from the required heating resistor (5) by the information signal. It is ejected and adheres to the recording paper.The internal space of the ink tank αυ is slightly negative and positive, and as the ink is consumed, the pressure becomes even more negative, and when it exceeds a certain value, the above pressure is released from the air port α&. Air flows into the ink tank through the vertical groove αe, etc., and returns to the original pressure, but the pressure fluctuation in this case is very small, so the nozzle (8)
The effect of the ink on the meniscus in this case is of little practical concern. The ink pressure in the nozzle (8) is determined by the distance from the nozzle (8) to the upper end position (a) of the vertical groove and the size of the upper end position of the vertical groove αe, and the ink surface in the ink tank αυ. It has nothing to do with height,
Regardless of the amount of ink consumed, the ink pressure at the position of the nozzle (1a) is always constant.Therefore, the ink ejection from the nozzle (8) is extremely stable.Also, immediately after ink is ejected from the nozzle (8) Even if air flows into the head from the nozzle (8) and bubbles are generated, the bubbles flow through the ink flow path (9) and through hole α to the ink tank αυ.
The nozzle plate (3) and the board (2)
) between the nozzle (8).
This does not impede the ejection of ink from the ink. Furthermore, when the air inside the ink tank expands due to temperature rise etc. and the internal pressure increases, the pushed out ink enters the vertical groove αG of the ink reservoir α2 and is further stored in the ink reservoir groove (5). Ink will not be inadvertently ejected from the nozzle {8}. The ink that has entered the ink reservoir @(15) is drawn back into the original ink tank as the air within the ink tank attempts to return to its original state and contracts.

(Effects of the Invention) The present invention is as described above, and the ejection of ink from the nozzle is extremely stable, and even if air enters the head from the nozzle and bubbles are generated, the bubbles are quickly removed. Since it escapes into the ink tank, there is no problem with ink ejection, and even if the air inside the ink tank expands due to a rise in temperature and the internal pressure increases, the ink is pushed out by the ink reservoir. This has the effect of preventing accidents such as being absorbed and being inadvertently discharged from the nozzle.

[Brief explanation of drawings]

Figure 1 is a perspective view, Figure 2 is a front view, Figure 3 is a front view with the nozzle plate removed, Figure 4 is a sectional view of the center, and Figure 5 is a cross section taken along the line A-A in Figure 4. 6 is a cross-sectional view taken along the line B--B in FIG. 4. (1)...Support, (2)...Substrate, (3)...
Nozzle plate, {4}...Gap, (5)...Heating resistor, (6)...Wiring, (7)...Contact, (8)...
Nozzle, (9)...Ink channel, αυ...Ink tank, α2...Ink reservoir, a3...Through hole, α之...Blade, α9...Ink storage groove, αe... vertical groove,
αa...Air port, ■...Ink guide rod, Kanji...Ink, Qυ...Ink reservoir. Figure 1 Patent Applicant: Mitsubishi Pencil Co., Ltd. (5)... Heating resistor {8)... Nozzle 09... Ink guide rod Diagram

Claims (1)

[Claims] A nozzle and means for ejecting ink droplets from the nozzle are disposed at the lower end of the support, and an ink flow path is provided in the support at a position above the means for ejecting ink droplets from the nozzle. An ink tank is mounted on the top surface, an ink reservoir is installed in the lower half of the ink tank, and the space above the ink reservoir is used as an ink reservoir. and an ink storage groove for storing ink pushed out from the ink storage section by an increase in internal pressure in the ink tank, and an ink guide rod is inserted into the through hole to communicate with the ink flow path of the support. An inkjet head further comprising a vertical groove that communicates between the ink reservoir groove and the ink reservoir, and also communicates the air port and the ink reservoir.